[PATCH] d3dx9: Check the square instead of the square root in D3DXSphereBoundProbe

[Alex Henrie]

Signed-off-by: Alex Henrie 
---
As far as I can tell, there is no need to call an expensive math
function here. In my tests, replacing the square root with a simple
multiplication on the other side of the equation reduces the time spent
in D3DXSphereBoundProbe by about 6% when the condition must be
evaluated.
---
 dlls/d3dx9_36/mesh.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/d3dx9_36/mesh.c b/dlls/d3dx9_36/mesh.c
index 5e0bb98efc..65c5ead7ba 100644
--- a/dlls/d3dx9_36/mesh.c
+++ b/dlls/d3dx9_36/mesh.c
@@ -2421,7 +2421,7 @@ BOOL WINAPI D3DXSphereBoundProbe(const D3DXVECTOR3 *pcenter, float radius,
     c = D3DXVec3LengthSq(&difference) - radius * radius;
     d = b * b - a * c;

-    if ( ( d <= 0.0f ) || ( sqrt(d) <= b ) ) return FALSE;
+    if ( ( d <= 0.0f ) || ( d <= b * b ) ) return FALSE;
     return TRUE;
 }